Free Radical Scavenging Effect of Ethanol Extract from Areca catechu

Abstract

Free radicals play detrimental roles in peroxidation of lipid, denaturation of protein, tumor, transformation, mutation, aging, and cancer [Simic, 1988]. To maintain healthy life and prevent quality deterioration of food by peroxidation of lipid, effective prevention of various diseases caused by free radicals is necessary. Researches are on-going for the development of antioxidants that inhibits the generation and activity of free radicals. BHA and BHT, which are synthetic phenol derivatives, have been widely used for commercial foods owing to their outstanding antioxidative activities; however, they are known through animal experiments to have various effects on, among others, the liver, lung, kidney, circulatory system, and reproductive system [Choe and Yang, 1982]. Thus, demands for plant-originated natural antioxidants with more stability and better antioxidation effects are increasing due to the rejection of synthetically produced ones by the consumers. Cha et al. [2000] reported the antioxidative activities of 30 species of the medicinal plants marketed in Korea. The antioxidative activities of 86 species of domestic native plants, 118 medicinal plants, 28 medicinal plants, and 32 medicinal plants were studied by Lim et al. [1996], Jeong et al. [2004], Kim et al. [1995], and Kim et al. [1995], respectively. The antioxidative activities of four mushroom species were studied by Kwon et al. [2008]. In spite of these studies, there still exist numerous frequently used medicinal plants, whose antioxidant activities have not been studied yet. In the present study, the antioxidative activities of the ethanol extracts obtained from selected medicinal plants, that are frequently used as food and herb medicine, have been evaluated by measuring their DPPH radicalscavenging activities. Here we report a herb species, which has an exceptionally high antioxidative activity effective for the elimination of the free radicals. The medicinal plants used in the present study were purchased from the Korea Medicine Herbs Association (Jeonju, Korea). The plants were ground into 80 mesh and stored at 4°C for use as specimen for extraction. DPPH, L-ascorbic acid, BHA, and BHT were purchased from Sigma Chemical Co. (St. Louis, MO). Approximately 10 g of each medicinal plant was separately put into 100 mL of 100% ethanol, extracted repeatedly at 37°C two times for 12 h each time. The solution was vacuumfiltrated twice through a filter paper (Whaman, No. 2), concentrated, and stored at −20oC until use. DPPH radical-scavening assay. The scavenging effects of the ethanol extracts against the DPPH radicals were determined according to the method of Yosida et al. [1989]. In brief, after dissolving the herbal ethanol extract with MeOH to concentrations of 120, 80.0, 40.0, 20.0, 10.0, 5.0, and 2.50 μg/mL, the prepared herb methanol solutions were each mixed with 1 mL of 0.15 mM DPPH solution. After standing for 30 min, the optical densities of the solutions were measured at 517 nm. The scavenging effects against the DPPH radicals were expressed as IC50 values. Scavenging effects of medicinal plants on DPPH radicals. Table 1 shows DPPH radical-scavenging activities of the ethanol extracts of 70 medicinal plants expected to have physiological activity. The medicinal plants with IC50 below 100 μg/mL were 11 kinds including Acorus gramineus Solander, those with IC50 below 50 μg/mL were 21 kinds including Arctium lappa L. Areca catechu L., Cassia tora L., Santalum album L., Terminalia chebula Retz, and Ulmus macrocarpa Hance, which have high radical scavenging activities, showed IC50 4.5, 8.0, 8.0, 7.0, and 6.0 μg/mL. Among these plant extracts, the ethanol extract of A. catechu L. showed the highest DPPH radical-scavenging activity. Kim et al. [1993] previously reported that methanol extract of Cullen corylifolium Medik. showed the strongest antioxidant activity among the methanol extracts of 120 medicinal plants by measuring lipid peroxides in a modeling system. The strong antioxidant activities of the methylene chloride extract of Scutellaria baicalensis Georgi, 75% ethanol extract of Caesalpinia sappan L. [Lim et al., 1996], 80% methanol extracts of *Corresponding author Phone: +82-63-850-0743; Fax:+82-63-850-0741 E-mail: ahn2002@chonbuk.ac.kr